<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>
<body>
  <button class="btn">切换</button>
  <div id="box" class="abc" title="aaa" style="color: red;">
    aaaaa
  </div>

  <script>

    var btn = document.querySelector(".btn")
    var box = document.querySelector("#box")

    btn.onclick = function(){

      // 隐藏
      box.hidden = "false"
      // 切换
      // box.hidden = !box.hidden
    }
  </script>
</body>
</html>